Stenciling apparatus with variable printing stroke



Feb. 15, 1955 H. A. GATTUSO STENCILING APPARATUS WITH VARIABLE PRINTING STROKE Filed Nov. 30, 1951 INVENTOR ATTORNEY United States Patent STENCILING APPARATUS WITH VARIABLE PRINTING STROKE Henry Andrew Gattuso, Adams, Mass. Application November 30, 1951, Serial No. 259,159

9 Claims. (Cl. 101-124) The present invention relates generally to a stenciling or printing apparatus of the type employing a silk screen and which is particularly designed for marking, lettering or otherwise decorating curved surfaces on cylindrical articles or the like as illustrated in my Patent No. 2,498,917 and as further more particularly disclosed in my pending application Ser. No. 141,323 filed January 30, 1950, now U. S. Patent 2,629,321, the same being made a part hereof and embodied in the present application by reference. The present application is a continuation in part of the last-mentioned patent. The type of machine disclosed in my patent and in the above appl cation is designed for operation upon small and medium sized articles ranging in diameter from very small cylindrical items which may have a diameter of a fraction of the ordinary conventional pencil and up to articles several inches in diameter. In this type of machine the stencil screen is reciprocated and the printing is effected by obtaining tangential contact between the curved surface of the article and the screen while the screen is moving in one direction or the other as desired, ink or paint being forced through the stencil by a squeegee.

The main objects of the present invention are to provide a power drive for this type of printing apparatus and also to provide for varying the travel length of contact between the work and the screen over a wide range to correspond to the amount of printing desired and to correspond with the angle of the are over which the printing is to be applied.

Other objects and advantages of the present invention will become apparent from the accompanying drawings and the following specification which illustrate one embodiment thereof.

In the drawings:

Figure l is a side view partly in longitudinal section of a machine embodying the present invention;

Figure 2 is an end view of the cam and drive assembly; and

Figure 3 is a sectional detail of a part of the drive assembly.

It is deemed unnecessary for the understanding of thepresent invention to include herein a full and detailed showing of all parts of the machine. The single longitudFnal sectional view of the machine adequately illustrates its principle of operation and the relationship of the parts thereof which enter into cooperation with the specific drive mechanism which will be described in greater detail. In the type of apparatus to which the present invention is applied the machine is preferably mounted upon a base and comprises a frame 11 mounted upon the base 10, the frame having for a primary purpose to support the screen carrier 12 and to provide for the reciprocal movement of the screen carrier together with the screen 16 therein. The screen 16 is secured within the frame 12 by the clamping screws 15. The work suport indicated as a unit by the reference character 13 is disposed below the screen carrier and provides for the ready insertion and removal of the work. It consists essentially of a pair of longitudinal bars 60 which are mounted for swinging or pivotal movement by means of the pn 78 which may be selectively inserted into any desired pair of recesses 76 provided in the frame members 11. The sliders 66 adjustably mounted on the bars 60 carry a pair of spindles 72 which are provided with slidable or adjustable collars 74 and thus provide a cradlelike support for the work and which may be adjusted to both the diameter and the length of the work. At its 2,702,001 Patented Feb. 15, 1955 forward end the cross member 61 of the work support unit carries a stud 80 which swings or pivots on the bar 61 at its upper end and is pivotally connected at its lower end to the operating bar 81 which extends rearwardly of the machine. Operating bar 81 is supported at an intermediate point to provide for adjustment of its vertical position within desired limits. For this purpose the sleeve or socket 86 is mounted on the base 10 and receives the bifurcated stud 87 which is pivotally attached to the operating bar 81 thereby permitting pivotal movement of the bar in the stud. The lower reduced portion of the stud 87 is threaded and carries the knurled nut 88 which serves as an adjustable stop for the stud 87. The sleeve 86 may also be provided with a set screw 89.

It will now be understood that in the operation of this machine the work is placed upon the work support when it is in the lower position as shown in full lines. By effecting a downward movement of the rear end of the operating bar 81 the work support together with the work carried thereby is raised to the dotted line position with the work in firm and tangential contact against the lower face of the screen 16. The screen may now he moved rearwardly and, with the cooperation of the squeegee or spreader unit 14, ink is forced through the screen 16 and received by the work.

The present invention aims particularly to provide the apparatus as thus far described with a power drive and with means for effectively coordinating the movement of the screen and the work support. Essentially it is important to control the length of contact between the Work and the screen so as to obviate and entirely eliminate any possible contact between the screen and the printed area on the work after the printing has been accomplished. The necessity for this control will be apparent when it is realized that the length of the screen may in some cases be many fold the peripheral dimension of the work. It is also true that whereas in some cases only a single line of printing occupying a small are on the periphery of the work is desired, in other cases several lines of printing may be desired occupying a large are upon the periphery of the work and perhaps entirely encircling the work. It therefore becomes important to control the operation of the machine in a manner so that printing should commence within a short length of travel after the work has been moved into contact with the lower face of the screen and that the work support should be moved downwardly within a short length of travel after the printing has been completed. Immediately thereafter the screen makes its idle return stroke, at which time the printed work is removed and a fresh piece of work is inserted and theoperation is repeated.

In order to accomplish these ends the present drive mechanism comprises a single unitary control assembly which is mounted on a single shaft and is driven by a small electric motor or the like. The single control and drive assembly indicated generally by the reference character 20 provides for reciprocating the screen carrier 12 within the frame 11 and this driving element may be adjustably fixed so as to vary and provide for the desired translational movement or length of stroke of the screen carrier. The same unit also provides cam devices for depressing the rear end of the operating bar 81, the cams being composed of several elements which may be adjusted so as to vary the time during which the work presses against the screen and thereby the length of contact travel of the work and screen is controlled.

The motor 21 mounted on the base 10 drives the unit 20 by the belt 23 and through the pulley 25. The shaft 31 is supported by the standards 33 which are fixed on the base 10. The standards 33 are preferably so mounted on the base 10 that the operating bar 81 is disposed between them. The shaft 31 at one end carries the drive disk 39 which is adjustably coupled to the screen carrier 12 to reciprocate the same in the frame 11. Any desired and suitable means for converting the rotary movement of the disk 39 into reciprocal movement of the screen carrier 12 may be employed.

As shown a bracket 41 is mounted on the rear end of the screen carrier 12 and this receives one end of the rod 43 for pivotal movement therein, the other end of the rod 43 being pivotally mounted on the block 57 which is slidable within the slot 59 in the drive disk 39. The screw 65 and nut 75 serve to secure the block-57 in the desired position in the slot 59. By means of the present coupling between the drive disk 39 and the screen carrier 12 the length of stroke of the reciprocal movement of the screen carrier is quite small when the block 57 is disposed at the lower end of the slot 59 or near the center of the disk. On the other hand, when the block 57 is at the upper end of the slot the length of stroke of the screen carrier will be at its maximum and will be many fold its minimum stroke.

The shaft 31 also carries two or more sector shaped cams 65 which are provided with a series of apertures 75 which serve to receive the bolt or screw 77 so that the degree of overlap between the two cams may be adjusted as desired so as to provide for a variation of length of contact between the cam surfaces and the pedal extension of operating bar 81. In addition the earns 65 may also be adjusted angularly of the shaft 31 and particularly with relation to the position of the slot 59 in the drive disk 39. For this purpose the shaft carries spacing collars 90 which may be loosened or tightened in position by Allen set screws 91.

It will be understood that the cam elements 65 employed may vary, depending upon the desired range of work. Essentially the cam of the present apparatus involves several overlapping sector-like portions which may fan out to provide for contact between the work and the screen over substantially 360, or it may be collapsed to provide only for a 15 or 30 contact.

When fanned out to their maximum the cam elements should occupy not more than 180 and for most purposes considerably below the 180. Only a half of a revolution of the drive unit includes a printing operation. The presentdrive unit therefore provides for effecting substantial equality between the printing contact and the printing stroke. This relationship results in clean and sharp printing and in a minimum of wear on the screen. As a result the quality of the work is high and the life of the screen is lengthened.

I claim:

1. A stenciling apparatus comprising a screen carrier mounted for reciprocating translational movement in a substantially horizontal plane and having a printin stroke and an idle return stroke, an article support disposed below the screen carrier and mounted for oscillatory movement for effecting contact between the article and screen during the printing stroke and breaking such contact during the return stroke to permit the replacement of the printed article by another, and means comprising a rotary shaft, a rotary element carried by said shaft, means coupling said rotary element to said screen carrier to reciprocate the carrier, means for adjusting the position of the coupling means on the rotary element to vary the stroke of the screen carrier, and cam means carried by said shaft and operable to effect said oscillatory movement of the article support, said cam means comprising a plurality of elements and means for adjusting said elements relative to each other to vary the period of contact between the article and the screen.

2. The apparatus set forth in claim 1 in which adjustment of the coupling means on the rotary element is effected along a line perpendicular to the axis of rotation of said rotary element.

3. The apparatus set forth in claim 1 which includes means for adjusting the relative angular positions of the rotary element andthe cam means upon the rotary shaft.

4. A stenciling apparatus comprising a printing means including a carrier for supporting a stencil, and a spreader mounted for traversing contact with a surface of the stencil for forcing a printing fluid through said stencil, a drive means for reciprocating said carrier and said spreader relative to one another, said drive means comprising an adjustable means for varying the stroke of said reciprocation, a work support disposed below the stencil carrier and mounted for oscillatory movement toward and away from the stencil to bring the work respectively into and out of printing engagement with said stencil, and a second drive means for etfecting said oscillatory movement, said second drive means comprising an adjustable means for varying the period of printing engagement of said work with said screen, thereby providing for control of the printing stroke and of the period of work and stencil contact during said printing stroke independently of one another.

5. The apparatus of claim 4 wherein the second drive means comprises a second adjustable means for varying the limit of movement of the work support toward the stencil, thereby enabling printing upon work articles of ditferent dimensions with controlled pressure between the work and the stencil during the printing operation.

6. The apparatus of claim 5 wherein the second drive means comprises a pivotally mounted lever, the second adjustable means in the second drive means comprises an elevating and lowering means for the lever pivot, and the first-mentioned adjustable means in the second drive means comprises an adjustable cam means on said lever to one side of said pivot to oscillate said lever about its pivot.

7. A stenciling apparatus comprising a printing means including a carrier for supporting a stencil, and a spreader mounted for traversing contact with a surface of the stencil for forcing a printing fluid through said stencil a drive means for reciprocating said carrier and s id spreader relative to one another, a work support di posed below the stencil carrier and mounted for oscillatory movement toward and away from the stencil to bring the work respectively into and out of printing e gagement with said stencil, and a second drive means for effecting said oscillatory movement, said second d means comprising an adjustable means for varying the period of printing engagement of said work with sai screen, and a second adjustable means for varvimz thlimit of movement of the worksupport toward the st cil, thereby enabling printing upon work articles of d ferent dimensions With controlled pressure between the work and the stencil during the printing Operation.

8. The apparatus of claim 7 wherein the second drive means comprises a pivotally mounted lever. the last-mentioned adjustable means comprises an elevating and lowering means for the lever pivot, and the first-mentione adjustable means comprises an adjustable cam means acting on said lever to one side of said pivot to oscillate said lever about its pivot.

9. The apparatus of claim 4 wherein the second drive means comprises a second adiustable means for varying the limit of contact pressure between the work and stencil, for effecting controlled pressure between the work and the stencil during the printing operation.

References vCited in the file of this patent UNITED STATES PATENTS Ian. 2, 1894 McCormick Dec. 30, 1952 

